Why Xiaomi Redmi Note 9 does not turn on: from a discharged battery to a “brick” after firmware

Why did your Redmi Note 9 become a brick?

You pressed the power button, but the screen of the Xiaomi Redmi Note 9 remained black — no logo, no vibration, no charging sound. The situation is familiar to many owners of this smartphone, released in 2020. The reasons can be both trivial (discharged battery) and critical (damaged motherboard). In this article, we will analyze all possible scenarios why the device does not turn on, and give specific instructions for each case, from simple manipulations to complex repairs.

It's important to understand that the Redmi Note 9 (codenamed merlin) has architecture features that affect diagnostics, such as its MediaTek Helio G85 processor, which is sensitive to voltage fluctuations, and its 5020 mAh battery is prone to deep discharge, which we will take into account in the recommendations. If you are not sure about yourself, you should contact a service center, especially if the phone does not respond to charging and does not warm up when connecting to the network (this is a sign of serious breakdown).

Let's start with the simplest and gradually move on to the hardest cases.

1.Discharged battery: how to distinguish from a breakdown?

The most common cause of a dead phone is a deep battery drain. The Redmi Note 9 may not show signs of life even if you plug it into a charger.

• 🔌 Connect the original cable and power supply (at least 18 watts) using uncertified accessories can block charging.
• ⏳ Wait 30 to 60 minutes. In a deep discharge, the battery controller may not respond immediately.
• 🔥 Check the temperature of the case near the charging port. If the phone is slightly heated, the battery will charge, but the indication does not work.
• 💡 Try another nest or power source (e.g., a different food source, USB-port).

If after an hour of charging, the phone still doesn't respond, move on to the next step, but first make sure the cable and adapter are working -- check them on another device.

⚠️ Note: Do not use “fast charging” from other devices (e.g., from other devices). POCO X3 The Redmi Note 9 power controller can block incompatible protocols, which will lead to even more discharge.

If the phone vibrates when charging, but does not turn on, this is a sign of a software failure (see section 4). If there is no reaction, the problem may be in the hardware (connector, battery, board).

2. Damaged charging connector or cable: how to diagnose?

The USB Type-C connector in the Redmi Note 9 is one of the most vulnerable points, and over time, the contacts oxidize, bend, or move away from the board.

• 🔍 Check the connector for contaminants. Use a flashlight and a magnifying glass. Garbage or corrosion can block contact.
• 🧲 Carefully clean the connector with a toothpick (not a metal object!). Use alcohol for oxidized contacts.
• 🔄 Try wiggling the cable in the connector, and if the phone starts charging in a certain position, the problem is mechanical damage.
• 🔌 Check the cable on another device. Sometimes it's not the connector that's damaged, it's the cord itself (especially on cheap accessories).

If the connector is visually damaged (for example, bent or wobbled), it must be soldered or replaced, this can be done at a service center for 800-1500 rubles. Self-repair without experience can damage the tracks on the board.

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If the USB-C connector is wobbling, do not try to "press" it yourself - this can tear the contact platforms from the board.

3. Hardware breakdowns: from battery to motherboard

If the phone doesn't respond to the charging and power button, the problem may lie in the hardware.

• 🔋 Bloated or dead battery: Redmi Note 9 is known for battery problems after 2-3 years of use. If the phone body is deformed, the battery needs to be replaced urgently.
• 🔥 Burnt-out power controller. Often occurs after using non-original chargers or power surges.
• 💧 Even if the phone hasn't sunk, condensation or high humidity can cause corrosion on the board.
• 🛠️ Damage after falling: Hits can disrupt soldering of chips or tracks, especially if the phone fell into a corner.

How to diagnose:

1. Remove the back cover (if you have experience) and inspect the battery. Bloating or leaking electrolyte is a clear sign of malfunction.
2. Smell the phone. The smell of the burn indicates burnt-out elements.
3. Connect the phone to charge and touch the case. If it heats up in the CPU area (top) but doesn't turn on, there's a PMIC problem.

⚠️ Warning: If the battery is swelling, do not try to charge it - this can lead to fire.Take the phone to the service for battery replacement (cost: 1000-2000 rubles).

To check the board, you need a multimeter and experience with electronics, and if you're not sure, you should trust the diagnostics to the professionals.

• Replacement of the power controller: 2000-3500 rubles.
• Restoration of tracks: 1500-4000 rubles (depending on the complexity).
• Replacement of the processor: 5000-8000 rubles (often unprofitable).

4. Software failures: bootloop, firmware and reset

If the phone vibrates, shows the Redmi logo and turns off (or loops on the boot) - it's a bootloop.

• ⚙️ Failed update MIUI.
• 🛠️ Wrong firmware through Fastboot.
• 🗑️ Conflict after the installation of custom recaveri (TWRP).
• 🧹 Failure after resetting settings.

How to fix it:

Method 1: Hard Reset (Hard Reset)

This will delete all data, but it will return the phone to working condition.

Turn off your phone (if it’s in bootloop, wait for the discharge)

Press the Power Button + Volume up for 10-15 seconds

From the Recovery menu, select Wipe Data → Wipe All Data

Confirm the reset and restart the phone-->

Method 2: Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fastboot Fast Fastboot Fastboot Fast Fastboot Fast Fastboot Fast Fastboot Fast FastBoat Fast Fast Fast FastBoat

If the reset didn't work, you'll need to run the official firmware.

1. Download the firmware for Redmi Note 9 (merlin code) from the Xiaomi Firmware website.

⚠️ Note: Fastboot removes all data, including photos and messages. If your phone had important files, try extracting them first. TWRP (if established).

If the phone still doesn't turn on after the firmware, the EFS partition (contains IMEI and modem data) may be damaged, in which case you will need specialized software (for example, Mi Flash Pro) and experience with it.

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If the phone shows an Invalid IMEI error after firmware or does not catch the network, this is a sign of damage to the EFS partition. It can only be restored using a backup or specialized tools (for example, Maui META).

5. Power button: mechanical breakdown or contamination

If the phone doesn't respond to the power button, but it's charging and being detected by the computer, the problem may be in the button itself.

• The button is “stuck” or pressed with difficulty.
• The phone is only activated after multiple clicks.
• There is a vibration when connecting the charging, but the screen does not light up.

How to fix:

1. Blow the button with compressed air (such as a keyboard cleaner), sometimes dust gets under the membrane.
2. Take the phone apart (if you have experience) and check the button plume. It may be moving away from the board.
3. Replace the power button. The cost of spare parts: 200-500 rubles, work: 1000-1500 rubles.

If the button is physically functional but the phone is not responding, the problem may be the power chip on the board, in which case a diagnosis is required in the service.

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Before disassembling the phone, take a picture of the location of all the plumes and screws. Redmi Note 9 has several types of screws (cross and five-pointed), they are easy to confuse.

6.Outside issues: How to roll back MIUI?

Many Redmi Note 9 users experience the phone stop turning on after the MIUI update.

• 🐛 Firmware bug (especially relevant for versions) MIUI 13/14 old-device).
• 🗃️ Lack of memory in the section /system.
• 🔒 Conflict with Root Rights or Magisk.

How to Reverse to the Previous Version:

1. Download stable firmware from the Xiaomi Firmware Updater website.
2. Go to Recovery (clip Power + Volume Up).
3. Select Apply update → Choose from storage and select the downloaded file.
4. Wait until the process is completed (don’t interrupt!).

If the phone doesn’t load even in Recovery, use Fastboot (see Section 4).

⚠️ Note: Retreat to an earlier version MIUI can block the bootloader if the phone was released with the bootloader locked. In this case, you will need to unlock through the Mi Unlock Tool (you need a Xiaomi account and device binding).

7. When should I contact the service?

There are situations where self-repair is not possible or advisable.

• 🔥 The phone overheats when connected to charging, but does not turn on.
• 💦 On the board visible traces of corrosion or burns.
• 🔋 The battery swelled or deformed the body.
• 🛠️ After a fall, the phone shows no signs of life (even vibrations).
• 🔄 Fastboot firmware ends with an error FAILED (remote: 'Not allowed in Lock State').

Average prices for repairs of Redmi Note 9 in 2026:

Before visiting the service, back up your data if your phone is responding to your PC connection. Use programs like Dr.Fone or Mi PC Suite.

FAQ: Frequent questions about the broken Redmi Note 9